Abstract:
This data set considers the PCBs, DDTs, CHLs, HCB and HCHs measured in blubber from Antarctic Type C killer whales and found that mean concentrations in all groups of POPs were significantly higher in adult males than in females. Type C whales had anyway the lowest mean concentrations for all groups of POPs, except for HCB. For example, the mean ΣPCB and ΣDDT concentrations in adult male Type C ... whales, relative to those from other five killer whale groups, ranged from 0.23% to 12% and from 0.12% to 20%, respectively. Conversely, mean HCB concentrations measured in Type C whales were comparable to others. PCB patterns in the blubber of the Antarctic Type C killer whales were also very different from those of the other killer whale populations, primarily due to a high relative abundance of higher chlorinated congeners (particularly PCB 149 and PCB 170) in Type C whales. Because point sources of pollution in Antarctica are relatively rare, the PCBs acquired by the biota from the region are generally the lower molecular weight congeners that can be transported via the atmosphere or ocean. However, 50 certain areas in McMurdo Sound have been documented to contain high, but patchy concentrations of the anthropogenically introduced Aroclor 1260 (one of several technical mixtures of PCBs) that contains the higher chlorinated congeners. Although it is not currently known if Type C whales are resident in Antarctica or whether they migrate to lower latitudes during the winter, migration could increase their exposure to pollutants. Regardless, Type C killer whales have the lowest levels of POPs (except HCB) of any killer whale population studied to date. In contrast POP concentrations in adult male Type C killer whales were found to be several times (5 to 90-fold) higher than those of male Antarctic minke whales sampled in western Antarctica (1992/1993, n = 20); and to the single Antarctic minke whale biopsied in 2006. Most of the differences in concentrations in the two species were likely due to the low levels of contaminants in krill that dominate the minke whale diet compared to higher levels of contaminants in fish or other higher trophic level species that comprise the Type C diet